Disintegratable films can provide a convenient and effective delivery vehicle for delivering active ingredients, such as pharmaceutical compounds, to a moist body surface of humans and animals. When exposed to moisture, for example, upon placement in the oral cavity, the film disintegrates and releases the active ingredient. However, the film should have adequate strength for processing and use as a unit dosage form, and also ensure appropriate release of the active ingredient while eliminating or minimizing any undue discomfort to the applied area.
U.S. Pat. Nos. 4,029,757; 4,029,758; and 4,031,200 refer to pharmaceutical dosage units formed from a multiplicity of edible webs that are sealed. One layer is fabricated by “fan folding” and compressing a continuous web structure, and subsequently sealing the composite into a geometric shape. The films rely on a complex process of fan folding and sealing to maintain the pharmaceutical compound internally within the multilayered dosage form.
U.S. Re 33,093 refers to controlled-release medicament-containing single or multi-layer thin films for intra-oral drug delivery. The thin film includes a polymeric matrix layer of 20-93% by weight of a hydroxypropyl cellulose having a molecular weight above 100,000; 5-60% of a homopolymer of ethylene oxide having a molecular weight from 3,000,000-5,000,000; 0-10% of a water insoluble polymer selected from the group consisting of ethyl cellulose, propyl cellulose, polyethylene and polypropylene; 2-10% of a plasticizer; and a pharmaceutically effective amount of medicament. The controlled-release films of U.S. Re. 33,093 are relatively slow to dissolve/disintegrate in the mouth.
U.S. Pat. No. 5,984,430 (Reexamination Certificate issued Mar. 4, 2003); U.S Pat. Nos. 6,177,096; and 6,284,264 refer to oral films for the delivery of pharmaceutical and cosmetic compounds. The compositions referred to in these patents contain a water-soluble polymer, a polyalcohol, a surfactant, and a pharmaceutically or cosmetically active ingredient. According to these patents, inclusion of the surfactant component imparts “instant wettability” followed by rapid disintegration of the film when placed into an aqueous environment such as the oral cavity.
U.S. Pat. No. 4,136,145 refers to a pharmaceutical unit dosage composition in which the pharmaceutically active medicament is uniformly dissolved or suspended in a flexible, water-soluble film carrier. The compositions include various drug compounds, water-soluble polymers, surfactants, release agents, parting compounds, and fillers.
U.S. Pat. Nos. 5,393,528 and 5,529,782 refer to dissolvable films for contraception or for the internal or topical delivery of a medication. According to these patents, the dissolvable films require the use of an inert gas to entrap bubbles in the polymer matrix to create a foamed film. The foam structure is required to control the dissolution rate and also to provide a perception of softness to the film.
Each film delivery system can be characterized by its film strength and its disintegration profile (the speed at which the film will disintegrate in an aqueous media, such as water, saliva and other bodily fluids, and/or in the presence of a trigger compound). Surfactants have been used to affect the disintegration speed and decrease the time required for complete film disintegration and thus release of the active ingredient. The present invention provides disintegratable film compositions that disintegrate upon exposure to moisture and/or a trigger compound, and which, at the same time, have sufficient film strength without requiring the use of any surfactant. While a surfactant is optional in certain embodiments of the present invention, as described below, other embodiments are surfactant-free or substantially free of surfactants.